1. Field of the Invention
The invention relates to a heating element, particularly a radiant heating element for heating glass ceramic plates in cookers with at least two separately operable heating zones with electrical heating resistors.
2. Prior Art
German Auslegeschrift 30 07 037, corresponding to U.S. Pat. No. 4,347,432 discloses a heating element with two concentric heating zones. It is desirable to greatly increase the power of the central heating zone, in order to achieve a short initial cooking or boiling time in the case of small cooking vessels. However, a power increase above a certain limit, e.g. 2100 W, is not possible, if the control is carried out with a timing power control device. The high making and breaking currents and the necessary switching rate lead to inadmissible loading of the mains. If the power of the central heating zone is raised at the expense of the other zones, an unfavorable heat distribution occurs on interconnection. It is also difficult to manufacture low power heating resistors for use at higher voltages, particularly 380 V, because the wires become too thin and are difficult to fix to the insulating body of the heating element.